Testing of Thermometers (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1911 Excerpt: ...a setting of about 200 C. From the observations a table is computed, giving the corrections to be applied at various points on the scale when the setting is 200. When another setting is used, the difference of temperatures, corrected by this table, must be multiplied by a factor depending on the setting. This factor will be unity for the setting 200. For other settings and for thermometers of Jena 16111 glass, graduated from o to 50 (or 6), the factors are given below: A similar table may be computed for thermometers of Jena 59111 glass or verre dur, but not so accurately for other glasses, as the departure from the gas scale, of thermometers made of other glasses, has not been studied with sufficient care. Metastatic thermometers should, therefore, be made of one of the three glasses mentioned. Stem Correction.--Griitzmacher" includes a stem correction in the setting correction. For this purpose he assumes that if the thermometer is used with a given setting, the stem tenperature will be sufficiently determined by this condition alone. If this were true, a modification of the factors given above could be made so as to take account of the stem correction. But on account of the difficulty of estimating the stem temperatures without knowing the conditions in which the thermometer is used, it would seem better for the user to determine and apply the stem correction separately. F'or calorimetric and Beckmann thermometers the stem correction may be computed as explained in section 9. 11 Zeitschrift fur Instrumentenkunde, 16, p. 200; 1896. D. LOW-TEMPERATURE THERMOMETERS For the measurement of temperatures below--350 C there are available alcohol, toluene, petroleum-ether, and pentane liquid in glass thermometers, copper-constantan and other thermocouples, a...